Reliability, Validity, and Responsiveness of InFLUenza Patient-Reported Outcome (FLU-PRO©) Scores in Influenza-Positive Patients

John H Powers 3rd; Elizabeth D Bacci; M Lourdes Guerrero; Nancy Kline Leidy; Sonja Stringer; Katherine Kim; Matthew J Memoli; Alison Han; Mary P Fairchok; Wei-Ju Chen; John C Arnold; Patrick J Danaher; Tahaniyat Lalani; Michelande Ridoré; Timothy H Burgess; Eugene V Millar; Andrés Hernández; Patricia Rodríguez-Zulueta; Mary C Smolskis; Hilda Ortega-Gallegos; Sarah Pett; William Fischer; Daniel Gillor; Laura Moreno Macias; Anna DuVal; Richard Rothman; Andrea Dugas; Guillermo M Ruiz-Palacios

doi:10.1016/j.jval.2017.04.014

Reliability, Validity, and Responsiveness of InFLUenza Patient-Reported Outcome (FLU-PRO©) Scores in Influenza-Positive Patients

Value Health. 2018 Feb;21(2):210-218. doi: 10.1016/j.jval.2017.04.014. Epub 2017 Jun 7.

Authors

John H Powers 3rd¹, Elizabeth D Bacci², M Lourdes Guerrero³, Nancy Kline Leidy⁴, Sonja Stringer⁴, Katherine Kim⁴, Matthew J Memoli⁵, Alison Han⁵, Mary P Fairchok⁶, Wei-Ju Chen⁷, John C Arnold⁸, Patrick J Danaher⁹, Tahaniyat Lalani¹⁰, Michelande Ridoré¹¹, Timothy H Burgess¹², Eugene V Millar⁷, Andrés Hernández¹³, Patricia Rodríguez-Zulueta¹⁴, Mary C Smolskis⁴, Hilda Ortega-Gallegos³, Sarah Pett¹⁵, William Fischer¹⁶, Daniel Gillor¹⁷, Laura Moreno Macias¹⁸, Anna DuVal¹⁹, Richard Rothman¹⁹, Andrea Dugas¹⁹, Guillermo M Ruiz-Palacios³

Affiliations

¹ Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research, Inc., NCI Campus at Frederick, Frederick, MD, USA. Electronic address: john.powers@nih.gov.
² Evidera, Seattle, WA, USA.
³ Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.
⁴ Evidera, Bethesda, MD, USA.
⁵ National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
⁶ Madigan Army Medical Center, Fort Lewis, WA, USA; Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA.
⁷ Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA.
⁸ Naval Medical Center, San Diego, CA, USA.
⁹ Defense Institute for Medical Operations, San Antonio, TX, USA.
¹⁰ Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA; Naval Medical Center, Portsmouth, VA, USA.
¹¹ Children's National Medical Center, Washington, DC, USA.
¹² Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Walter Reed National Military Medical Center, Bethesda, MD, USA.
¹³ Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico City, Mexico.
¹⁴ Hospital General Dr. Manuel Gea González, Mexico City, Mexico.
¹⁵ University College London, London, UK; Kirby Institute, University of New South Wales, Sydney, New South Wales, Australia.
¹⁶ University of North Carolina, Chapel Hill, NC, USA.
¹⁷ Cologne, Germany.
¹⁸ Hospital General de Agudos JM Ramos Mejia, Buenos Aires, Argentina.
¹⁹ Johns Hopkins University School of Medicine, Baltimore, MD, USA (for the INSIGHT Flu 002 Plus Writing Group, the México Emerging Infectious Diseases Clinical Research Network, and the Infectious Diseases Clinical Research Program).

Abstract

Objectives: To assess the reliability, validity, and responsiveness of InFLUenza Patient-Reported Outcome (FLU-PRO©) scores for quantifying the presence and severity of influenza symptoms.

Methods: An observational prospective cohort study of adults (≥18 years) with influenza-like illness in the United States, the United Kingdom, Mexico, and South America was conducted. Participants completed the 37-item draft FLU-PRO daily for up to 14 days. Item-level and factor analyses were used to remove items and determine factor structure. Reliability of the final tool was estimated using Cronbach α and intraclass correlation coefficients (2-day reliability). Convergent and known-groups validity and responsiveness were assessed using global assessments of influenza severity and return to usual health.

Results: Of the 536 patients enrolled, 221 influenza-positive subjects comprised the analytical sample. The mean age of the patients was 40.7 years, 60.2% were women, and 59.7% were white. The final 32-item measure has six factors/domains (nose, throat, eyes, chest/respiratory, gastrointestinal, and body/systemic), with a higher order factor representing symptom severity overall (comparative fit index = 0.92; root mean square error of approximation = 0.06). Cronbach α was high (total = 0.92; domain range = 0.71-0.87); test-retest reliability (intraclass correlation coefficient, day 1-day 2) was 0.83 for total scores and 0.57 to 0.79 for domains. Day 1 FLU-PRO domain and total scores were moderately to highly correlated (≥0.30) with Patient Global Rating of Flu Severity (except nose and throat). Consistent with known-groups validity, scores differentiated severity groups on the basis of global rating (total: F = 57.2, P < 0.001; domains: F = 8.9-67.5, P < 0.001). Subjects reporting return to usual health showed significantly greater (P < 0.05) FLU-PRO score improvement by day 7 than did those who did not, suggesting score responsiveness.

Conclusions: Results suggest that FLU-PRO scores are reliable, valid, and responsive to change in influenza-positive adults.

Keywords: influenza; patient-reported outcome; psychometric; reliability; responsiveness; validity.

Publication types

Observational Study
Research Support, N.I.H., Extramural
Research Support, N.I.H., Intramural

MeSH terms

Adult
Factor Analysis, Statistical
Female
Humans
Influenza, Human / epidemiology
Influenza, Human / physiopathology*
Male
Patient Reported Outcome Measures*
Prospective Studies
Psychometrics
Reproducibility of Results
Severity of Illness Index*
United States / epidemiology

Abstract

Publication types

MeSH terms

Grants and funding